Means for the production of thin and very thin foils and film-like bands from soluble cellulose derivatives



Se t. 22, 1931. E|HENGRUN 1,824,337

MEANS FOR THE PRODUCTION OF THIN AND VERY THIN FOILS AND FILM LIKE BANDS FROM SOLUBLE CELLULOSE DERIVATIVES Filed Oct. 16, 1925 2 Sheets-Sheet 1 ,fivenlizr: Ari/2 Eichengltz'in Y ar Sept. 22,1931. A. EICHENGRUN 1,324,337 MEANS FOR THE PRODUCTION OF THIN AND VERY THIN FOILS AND FILM LIKE BANDS FROM SOLUBLE CELLULOSE DERIVATIVES Filed Oct. 16, 9 5 2 Sheets-Sheet 2 INVENTOR ARTHUR EICHENGRUN aluminium or the like,

a face.

12 to 16 metres.

Psreatee Sept. 22, 1931 UNITED STATES ARTHUR mormuonfliw,

OI CHAB'LOT'I'ENBURG, GERMANY, ASSIGNOR TO CELANESE CORPORATION OF AMERICA, A CORPORATION OF DELAWARE MEANS FOR THE PRODUCTION OF THIN AND VERY THIN FOILS AND FILM-LIKE BANDS FROM SOLUBLE CELLULOSE DERIVATIVE Application filed October 18, 1925, Serial No. Q2988, and in Germany October 20, 1924.

Thisinvention relates to apparatus 'for the production of endless films from soluble cellulose derivatives, t

In practice, film-like bandsof solutions of cellulose derivatives such as nitro-cellulose, acetyl-cellulose, alkyl-cellulose, and the like are manufactured exclusively by pouring solutions of these products onto a rigid ase. Such rigid bases ma comprise .a pouring table or a solid or ho ow metal cylinder in which case the layeris face or into the interior of the cylinder, or rollers of stone, hard rubber or a similar material havinga surface capable of takingup.

n polish, or a rigid band of copper, nickel, which is passed over two or more drums at suclra high tension that the band always presents a smooth sur- Such a method of operation obviously entails the pouring machines working very slowly since it has been found in practice that it-is only possible to obtain satisfactory results if the pouring drums have a maximum diameter of 2 to 3 metres and if the overall length of theendless bands amounts to about In such cases the cellulose layer must becompletelydried within the period of'one cycle of operations so that in order to be able to ensure stripping of the band of foil, the drying period must b9 made as long as possible and consequently the speed of the bases must be as slow as possible. In these circumstances an output of onlyabout 40 square metres per hourcan be expected, in the manufacture of films on a usual pouring machine.

Attempts stitute for rigid bases, pliable materials such as impregnated paper, oil cloth, rubberized fabrics or .very

after passing In; such cases the bands were,

beneath the pourer, over the tables or rollers;

conveyed horizontally for long distances until the solutions had dried and could no longer run ofi laterally Thereupon they were re; turned, in accordance with the above described method to the poureror to a secondbandapparatus which served mainly for the poured onto the surhe have often been made to sub-- 7 thin sheets of-metal, in order to obtain greater lengths of drying surface.-

Apart from the factthat the constructional arrangements for this purpose were very complicated, this methodhas not proved practicable because after the bases had been in use for some time, they altered owing to the formation of folds, warping, denting and tears at the edges, to such an extent that the applied solutions dried irregularly and that film bands thus produced were irre lar in structure and thickness. Above all owever owing tothe constant strain, the pliable materials became in time so warped that the edges were more strongly tensioned than the middle. The middle was therefore lifted from the guide edges were applied thereto so that rounded surfaces were produced upon which the poured mass failed to adhere or only adhered in thinner layers than at the edges. This disadvantage was particularl noticeable in' the production of very thin fi of a thickness of lessthan 0.1 millimetres since in such case the reduction of the already ve sinall thickness led to tears and to the prim d of faulty portions and hitherto made it impossible to employ long band-like bases for the manufacture of thin'films.

It has now been found that it is ssible to produce not only films but above a also,.the,

very 'thinnestifoils of 0.03 millimetres down perfect nature, in an extraordinarily rapid operation. Such foils can for example be manufactured .in lengths of about 5 metres or more per minute, if instead of using the usual thinly liquid solutions which were applied to the bases by spraying or by a brush'or by passing through narrow slots, solutions were used which by virtue of their high concentration, high viscosity, capability of rapidly solidifying, in consequence of the composition of the solvent mixture for the purpose in (gleetion, already solidify or. adhere to the ase after ashort time, oif from the'base or are displaced thereupon in such a' way that the thickness ofthe layer varies.

uctionso that they no longer run.

- china and no shortening a base consisting of a long loose band 100 or 200 metres or more long. This-band consists of a rigid but pliable material such as for example cardboard, sheet metal, cellulose filmi linoleum, rubberized material or the likean is of such a thickness as not to fold, tear or layer. If desired, the base may be coated with other materials such as for example gelatine, starch, rubber, albumen or cellulose deriva-tives toprevent-oxidation, or any actionof the' cellulose derivative solvents or to produce smoother surfaces or vice versa, or to produce a matt or ornamented surface, or to increasethe separability of the coating.

The bands are preferably first conveyed over a coating drum or coating table in a horizontal direction in order to 've the ap plied cellulose mass time to solidify or to commence to dry, so that it no longer flows off when the band moves out of the horizontal direction and is thereupon led to a loopway which enables the band to be suspended in the form of loops. This loop-way difiers considerably from the usual drying devices such asemployed in thefpaper industry. Thus the bands are no longer suspended from rods since they would undergo creasing. Instead of this, they are assed over roller like devices or upon broad e ges or discs of a-considerable diameter which preferably corresponds to the natural radius of curva-. ture of 'thebands and which differs with the material from whichthe bands are produced and their thickness. This measure prevents all creases and dents in the base which would have an unfavourable efiect on the foils to be produced. I Moreover, the individual loo s are not as on the rod carriers, butthe bands themselves I T hitherto usual, conveyed by bemg displaced loops. This isefiected by causing the suspending device for example tubular-or solid I metal rollers to rotate in a fast hearing. The

band which is preferably-moved forage-rd at both edges by driving wheels, is

passed over one guide roller and conveyed in the form of a loop to the next following one. The conveying orguide rollers are driven'by meansof a belt drive, pinion or worm ing device so that the band-like base is moved forwarduniformly' in all portions of the map p or lengtheningof the loops'can take place. I By means of thea paratusit' is 'ble'to arrange a very long ength'of ban in a rela-' warp after the application of the cellulose move forward; continuously in the forni of' p .which run in the inner gear-- ing synchronously with the drive of the pour-f tively small space since in working rooms of normal hei ht, loops of about 10 metres length can s arranged so that a length of band of about 200 metres only takes up about 20 metres length of room.

In contradistinction. to the usual film-pouring methods where the films must be unrolled when only about 15 metres long, the present apparatus enables long lengths of foil to be poured and dried on their base whilst-simultaneously greatly increasing the speed of. pouring. This is of particular importance for the production of very thin foils which are produced in entirely insufi'icient quantities in the usual film pouring machines. In this method of operation it is of particular importance that the foils must be conveyed on their bases in a uniform manner over all portions of the loop-way or .dryin device. Whilst a very irregular drying was efiected in the usual'loop-ways because portions of 'theband at the upper parts ofthe loop-way dried more rapidly 'thanthe innerand lower portions of the loops where there was practically no movement of air, according to the present invention thebases with the drying foils continually move forward at a uniform speed throughout the whole apparatus so that each portion of the band is dried under the same conditions as any other It is moreover possible by means of this continuous advancing movement, to subject the bands to successively different drying conditions, tered in individual portions by aeration, or heating or by' cooling or aspiration or the like. In particular, it is possible in this manner to aspirate the solvent vapours for recovery, at those. places where maximum" evaporation takes place because fresh amounts of solvent returning from thence beneath the loop-wa to the pouring device. The rolling off oft 0 dried film can be effected both at the end of the machine or also atthe beginning thereof shortly before-the pension of the bands atthe 11 1s ssible to v on y, one can: -on. the. obverse and reverse side of the For this ,purpose instead," ofthe liouringjtableor pourinlgl'drum a device. I is 'em eyed, ch a cellulose I means of w 5011113011 the drying conditions being al-- 18 #PP fed to the. verticall gear wheels or b a y I p thus a nsm also forlthe's us 1 pper. loops, it

ro'duoetwo fo ls ,simultan the guide-rollers,

, straln imposed thereon by the suspenslon of the edges. For this purpose thin hard metal bands or thick'film's of celluloid or acetyl cellulose are suitable which if vdesired, may serve as carriers for further base material such as for example for tin foil,-prepared .films as consist of several layers of diflerent.

papers or fabrics or similar materials upon which the solution is thereupon applied.

This apparatus is suitable also for the production of thick films consisting of several layers of a uniform material and also of such cellulose derivatives or several compositions in respect of contents in 'filling materials, softening agents, dyes, pi ments and the like. For the purpose of pro ucing such thicker layers, the band is caused to rotate beneath the pouring device continuously, the latter being so arranged that on applying each sub-'; sequent layer it is displaced correspondingly. Alternatively a second pouring device and if desired several more of such pouring devices may be arranged at some distance from the pouring device which additional pouring devices are adaptedto apply a second and third layer shortly after drying of the pre-' superimposed, the

Nevertheless','the 1ndividual layers can after.

- On theother hand-also b infiammability,

vious layer the composite layers being thereupon dried in the loop-way. It has been fou d that layers from solutions of the samecomposition combine firmly to other so that films of a greater thickness an particularly of a greater length are produced than was hitherto possible with the usual film-making machines. If solutions of difierent composition'sucn as for example solutions of'nitrocellulose, cellulose acetate, ethyl cellulose, are

dry'into a uniform film,

drying, be wound up as se 'arate-coherent lm so that several film's 0 different kinds may be produced simultaneously;

he addition of suitable substances, especia 1y camphor substitutes, films of various cellulose derivatives difierin from each other, -such as nitro-cellue lose an cellulose acetate may becombined together-to produce film'sfwhich consist of in ivi'dual layers ofjdi'fierent' composition, rigidity and sensitiveness to water. i

.This is of special importance. because in the-production of such doublelayers, the

ayer had to .be produced as a second layer long filament and wound up, whereupon 'the a separate operation, in which it was diflicult to avoid softening and distortion of the first layer.

According to the present invention how ever the first and as well as all subsequent layers remain firmlyB connected to the baseuntil the final drying. Any softening or swelling owing to. solvents contained in the further layers to be applied has no detrimental effect.

It is even possible to efiectpreliminary preparation and even the emulsioning of the films prior .0 removing them from the base without any detrimental influence upon the films.

In order more'clear'ly to understand the invention reference is made to, the accompanyingdrawings which illustrate diagrammatically and byway of example, one embodinient of machine constructed in accordance therewith and inwhich Fig. 1 is a side elevation of the apparatus;

Fig. 2 is an end elevation from the righthand side -of Fig. 1, and

Fig, 3 is a side elevation of part ofthe apparatus showing means for casting films or foils on both sides of the travelling band.

The machine consists of an endless band B of a considerable length of for example 50, 100 or even 200 metres, which passes over a drum A above which. is arranged the supply hopper G for the cellulose'derivative soluhad to be applled to this film in tion said hopper G may if desired co-operate with scraping devices not shown adapted evenly to distribute the cellulose derivative solution on the travelling band B.

. After passing beneath the a the band travels horizontally ora short distanoe'in order to prevent the cellulosederivative solution from flowing off the band im-' mediately after application thereto. Thereupon the band moves vertically downwards over ,a hollow or recessed roll a rising vertically and passing over a similar hollow or recessed upper roll 1) indicated in lateral elevation in dotted lines in Figure 2 of the drawings, and travels in succession over the next lower roll a upper roll b, lower roll (1, upper roll b, finally 'lpassing over the lower roll a and upper to b from whence it is'conducted over ide' rolls c 0', c to the point where e d filmis stripped from the travelling ban and woun n roll C.

y rolls, .thetravelling. rolls only to. either or both sides of the band is prevent ed from coming into contact with any solid surface during-its drying. It is however ob-' 'ther' the series of lower rolls l per rolls desired virtue of the employment of hollow band contacts with the b maybe solidif itis plymg device at its edges so that the film applied In the embodiment illustrated the series.

' of upper rolls 6', b, b b are driven in pulleys p and bevel synchronism by an electromotor it through gearing 9 indicated diagrammatically.

The upper rolls 6', b, b b are each mounted in separate bearings is connected to common supports Z whereas the lower idle rolls a, a a. a are mounted in a com,- mon frame f.

Any or all of the rolls a, b, 0 may be pro vided with flanges m adapted to form guides for the travellingband. 2.

Fig. 3 shows means for castingfilms'or foils on both sides of the travelling band B. As shown in this figure-there are provided two vessels or troughs t, t which .contain a solution of the derivative of cellulose. In

these troughs, pick-up rolls r, r rotate and take up the solution of the derivative of cellulose from the vessel or trough and transfer it to the rotating rolls 8, s, which'in turn apply the solutionlto the band B as it comes down from the guide roll d; The films on foils that are formed are stripped from the band and are wound on the rollsD.D'.

I claim I 1. In apparatus for producing continuous film bands of cellulose derivative, the combi .nation of supply means for a solution of cellulose derivative, a travelling band repellant to the said cellulose derivative when solidified and passing beneath said supply means, and means for removing said cellulose derivative solution solidified from said band, said band being arranged in the form of loops uniformly individually positively driven and supported by its borders only.

2. In apparatus for producing continuous film bands of cellulose derivative, the combination of supply means for asolution of cellulose derivative, a travelling band repellant to the said cellulose derivative when solidified and passing beneath said supply means, a plurality of recessed rolls contacting with said band at its borders only and arranged in such a manner that said band forms a series of loops and means for removing said cellulose 50' derivative solution solidified from said band.

3. In apparatus for producing continuous film bands of cellulose derivative, the combination of supply means for a solution of cel lulose derivative, a travelling band repellant to the said cellulose derivative when solidified and passing beneath said supply means, a plurality of recessed rolls contacting with said band at its borders only and arranged in I such a manner that said band forms a series of loops, means for driving said rolls in synchronism and means for removing said cellulose derivative solutiori solidified from said band. 4. Inapparatus for producing continuous film bands of cellulose derivative the combination of supply means for a solution of cellulose derivative-a. travelling bandrepellant to the said cellulose derivative when solidiofsolid rolls in such a manner as to arrange said band in the form of a series of loops and means for removing said cellulose derivative solution solidified from said band. a

5. In apparatus for producing continuous film bands of cellulose derivative the combination of supply means for a solution of cellulose derivative, atravelling band repellant to the said cellulose derivative when solidified and passing beneath said supply means, a series of recessed rolls contacting with said band at its borders only coacting with a-series of solid rolls insuch a manner as to arrange said band in the form of'a' series of loops, means for driving one of said sets of rolls in synchronism, and means for removing said cellulose derivative solution solidified from Said band. y v

6. In apparatus .for producing continuous film bands of cellulose derivative the combi lose derivative when solidifie a plurality of recessed rolls contacting with said band at its.

borders only and arranged in such a manner that said band forms-a series of loops, means for applyin cellulose derivative solution to both sides 0% said band and means for remov ing the films of said cellulose derivative solu tion when solidified from said band.

fl. In apparatus or producing continuous film bands of-cellu ose. derivative the-combination of supply ans for a solution of collulose derivative, a travellinglband comprising metal and a repellant to t derivative when solidified and passing bee said cellulose neath said supply means, a plurality of reborders only and, arranged in such a manner that said band forms a series of loops and i means for removing said cellulose. derivative] solution solidified from said-band.

8. In apparatus for producing continu-' ous film bands of cellulose derivative the combination of supply means for a solution of cellulose derivative, a travelling band repellant to the said cellulose derivative when solidified and passin beneath said supply means, a pluralityo alternate upper and lower recessed rolls contacting with said band at its borders only and'arranged in such a manner that said band forms a seriesof loops,

nation of supply means for a solution of cellulose derivative, a travelling band recessed rolls contacting with said band at its for removing the films of said cellulose derivative solution when solidified from said band.

10. In apparatus for producing continuous filmbands of cellulose derivative the combination of supply means for a solution of cellulose derivative, a travelling band repellant to the said cellulose derivative when solidified and passing beneath said supply means, a series of alternate upper rolls alternating with a series of lower rolls, one series comprising recessed rolls contacting with said band at its borders only and coasting with the other series comprising solid rolls in such a manner as to arrange-said band in the form of a series of loops, a support common' to the upper rolls, a support common to the lower rolls and means for removing the films of said cellulose derivative solution when solidified from said band.

11. In apparatus for producing continuous film bands of cellulose derivative the comof cellulose derivatives, a travelling band repellant tothe said cellulose derivative when solidified and passing beneath said supply means, a series of recessed rolls contacting with said band at its borders only coacting with a series of solid rolls in such a manner as to arrange said band in the form of a series of loops, guide means for said band at the edges of said rolls, means for driving one of said sets of rolls in synchronism and means for removing said cellulose derivative solution solidified from said band.

14:. In apparatus for producing continuous film bands of cellulose derivative the.

combination of supply means for a solution of cellulose derivative, a travelling band repellant to the said cellulose derivative when solidified and passingbeneathsaid supply means, a series flanged of recessed rolls contacting with said band at its borders only coacting with a series of flanged solid rolls in such a manner as to arrange said band in the form of a series of loops, means for driving one of said sets of rolls in synchronism and means for removing said'cellulose derivative solution solidified from said band.

In testimony whereof, I afii x my signature.

I ARTHUR EICHENGRIIN.

bination of supply means for a solution of I cellulose derivative, a travelling band repellant to the said cellulose derivative when solidified and passing beneath said supply means, a series of alternate upper rolls alternating with a series of lower rolls, one series comprising recessed rolls contacting with said band at its border only and coacting with the other series comprising solid rolls in such a manner as to arrange said band in the form of a series of loops, a support common to the upper rolls, a support common to the lower rolls, means for driving one series of rolls in synchronism and means for removing the films of said cellulose derivative solution when solidified from said band.

12. In apparatus for producing continuous film bands of cellulose derivative the combination of supply means for .a solution of cellulose derivative, a travellingband repellant to the said cellulose derivative when solidified and passing beneath said supply means, a series of recessed rolls contacting with said band at its borders only coacting with a series of solid rolls in such a manner as to arrange said band in the form of a seriesof loops, means for driving one of said sets of rolls in synchronism, a plurality of.

different d ing zones traversed by said band and means or removing said collulose derivative solution solidified from saidband.

13. In apparatus for producing continu-. 

